Southeast to south winds will occasionally gust to around 20 knots through late evening over the Lower Tidal Potomac River and middle Chesapeake Bay. Inexperienced mariners, especially those in small craft, should exercise caution and be prepared for locally higher winds and waves.

* WHAT. For the Heat Advisory, heat index values ranging from 95 to 100 degrees. For the Excessive Heat Watch, dangerously hot conditions with heat index values ranging from 100 to 105 degrees possible. * WHERE. Portions of northern Delaware, central, northern, and southern New Jersey, and southeast Pennsylvania. * WHEN. For the Heat Advisory, until 6 AM EDT Saturday. For the Heat Advisory, the hottest temperatures and heat indices are forecast to occur on Friday. For the Excessive Heat Watch, from Saturday morning through Sunday evening. * IMPACTS. Heat related illnesses increase significantly during extreme heat and high humidity events.

* WHAT. Heat index values up to 100. * WHERE. Central Pennsylvania. * WHEN. Until 8 PM EDT Saturday. * IMPACTS. Hot temperatures and high humidity may cause heat illnesses.